The effect of ply properties in paperboard converting operations: a way to increase formability

Cellulose - This study addresses the question of how the difference in mechanical properties of the individual layers in a multi-ply commercial paperboard affects the outcome of the tray-forming...     

Conditions for sulfite stabilization and determination by ion chromatography

The efficiencies of three groups of potential sulfite-stabilizing compounds were found to be in the order: carbonyls > alcohols = saccharides. A mole ratio of 1:1 between formaldehyde and sulfite was sufficient for stabilizing a sulfite solution for at least 72 h. The lower stabilizing efficiencies of the alcohols and saccharides examined could be compensated by using large excesses of these compounds. For example, if a 100-fold excess of glycerol over sulfite was used, the recovery of sulfite was 96% after 72 h compared with only 40% without addition of stabilizer. During separations by ion chromatography, almost no oxidation of the sample occurs provided the sample solution is directly injected into a deaerated eluent. For formaldehyde, the peak heights were found to depend on the molar ratio of the stabilizer to sulfite as well as on the concentration of sulfite. This effect was not found for the other stabilizers tested.     

Automatic coulometric titration with photometric end-point detection : Part I. A coulometric titrator based on differential photometric detection

A system for automatic coulometric titrations with photometric end-point detection is described. To compensate for errors caused by gas bubbles and turbidity, the beam is split after passing the titration cell. The intensities of the respective light beams are registered by means of two photodiodes operating in the current mode. The currents are converted to voltages and the logarithm of the quotient is taken. The measured absorbance is only slightly dependent on the variation in the intensity of the incident light. A diminution of one absorbance unit causes a relative error of less than 5%. The deviations due to carbon particles (37–75 μm) were less than 0.002 absorbance units per mg of carbon present in 10 ml of solution. The improvement with respect to errors caused by gas bubbles is illustrated. The fundamental advantage of a one-lamp system over a twolamp system is shown.     

Single-frequency operation of a high-power, long-wavelength semiconductor disk laser

An optically pumped, high-power, single-frequency semiconductor disk laser is demonstrated. A thin (50 microm) diamond bonded to an InGaAsP gain chip provides the combined functions of heat removal and spectral filtering, thus eliminating the need for the additional intracavity etalons that are usually employed for single-frequency operation. In a short cavity (4 mm) configuration we obtained a maximum output power of 470 mW at 0 degrees C and 170 mW at 20 degrees C in a near-diffraction-limited beam (M2 < 1.2). The emission wave-length was 1549 nm and the linewidth was less than 200 MHz.     

Thio arsenosugars identified as natural constituents of mussels by liquid chromatography-mass spectrometry

Two novel thio arsenosugars have been identified by liquid chromatography-mass spectrometry as significant arsenic constituents in samples of mussels.     

High-throughput screening of pKa values of pharmaceuticals by pressure-assisted capillary electrophoresis and mass spectrometry

A high-throughput pKa screening method based on pressure-assisted capillary electrophoresis (CE) and mass spectrometry (MS) is presented. Effects of buffer type and ionic strength on sensitivity and pKa values were investigated. Influence of dimethyl sulfoxide (DMSO) concentration present in the sample on effective mobility measurement was examined. A series of ten volatile buffers, covering a pH range from 2.5 to 10.5 with the same ionic strength, was employed. The application of volatile background electrolytes resulted in significant signal increase as compared with commonly used non-volatile phosphate buffers. In general, the CE/MS system provided a ten-fold higher sensitivity than conventional UV detection. The newly developed CE/MS method offers high-throughput capacity by pooling a number of compounds into a single sample. Simultaneous measurement of more than 50 compounds was readily achieved in less than 150 min. The measured pKa values are consistent with the published data obtained from the CE/UV method and are also in good agreement with data generated by other methods. Other advantages of using CE/MS for pKa screening are illustrated with typical examples, including poorly soluble compounds and non-UV-absorbing compounds.     

Reduced expression of <Emphasis Type="Italic">TAC1</Emphasis>, <Emphasis Type="Italic">PENK</Emphasis> and <Emphasis Type="Italic">SOCS2</Emphasis> in <Emphasis Type="Italic">Hcrtr-2</Emphasis> mutated narcoleptic dog brain

Background  

Narcolepsy causes dramatic behavioral alterations in both humans and dogs, with excessive sleepiness and cataplexy triggered by emotional stimuli. Deficiencies in the hypocretin system are well established as the origin of the condition; both from studies in humans who lack the hypocretin ligand (HCRT) and in dogs with a mutation in hypocretin receptor 2 (HCRTR2). However, little is known about molecular alterations downstream of the hypocretin signals.     

Optimal closing of a pair trade with a model containing jumps

A pair trade is a portfolio consisting of a long position in one asset and a short position in another, and it is a widely used investment strategy in the financial industry. Recently, Ekström, Lindberg, and Tysk studied the problem of optimally closing a pair trading strategy when the difference of the two assets is modelled by an Ornstein-Uhlenbeck process. In the present work the model is generalized to also include jumps. More precisely, we assume that the difference between the assets is an Ornstein-Uhlenbeck type process, driven by a Lévy process of finite activity. We prove a necessary condition for optimality (a so-called verification theorem), which takes the form of a free boundary problem for an integro-differential equation. We analyze a finite element method for this problem and prove rigorous error estimates, which are used to draw conclusions from numerical simulations. In particular, we present strong evidence for the existence and uniqueness of an optimal solution.